#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>

int main()
{
	int ret = 0;
	int digits[10] = { 1,1,2,2,3,3,4,5,5 };
	for (int i = 0; i < 9; i++)
		ret ^= digits[i];
	printf("%d\n", ret);
	return 0;
}